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Composer's missing argument delimiter can lead to code execution via VCS repository URLs or source download URLs on systems with Mercurial

High severity GitHub Reviewed Published Apr 27, 2021 in composer/composer • Updated Jan 24, 2024

Package

composer composer/composer (Composer)

Affected versions

< 1.10.22
>= 2.0.0-alpha1, < 2.0.13

Patched versions

1.10.22
2.0.13

Description

URLs for Mercurial repositories in the root composer.json and package source download URLs are not sanitized correctly. Specifically crafted URL values allow commands to be executed in the HgDriver if hg/Mercurial is installed on the system.

Impact

  • The impact to Composer users directly is limited as the composer.json file is typically under their own control and source download URLs can only be supplied by third party Composer repositories they explicitly trust to download and execute source code from, e.g. Composer plugins.
  • The main impact is to services passing user input to Composer, including Packagist.org and Private Packagist. This allowed users to trigger remote command injection. The vulnerability has been patched on Packagist.org and Private Packagist within 12h of receiving the initial vulnerability report and based on a review of logs, to the best of our knowledge, was not abused by anyone.
  • Other services/tools using VcsRepository/VcsDriver or derivatives may also be vulnerable and should upgrade their composer/composer dependency immediately

Patches

1.10.22 and 2.0.13 include patches for this issue.

References

@Seldaek Seldaek published to composer/composer Apr 27, 2021
Reviewed Apr 27, 2021
Published by the National Vulnerability Database Apr 27, 2021
Published to the GitHub Advisory Database Apr 29, 2021
Last updated Jan 24, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

11.746%
(96th percentile)

Weaknesses

CVE ID

CVE-2021-29472

GHSA ID

GHSA-h5h8-pc6h-jvvx

Source code

Credits

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